, Rio de Janeiro, Vol. (7), November 2015
Compound 5 [α]
identified by infrared (IR) (KBr,ν
), ultraviolet (UV) λ (EtOH, Max) nm (log ε), 224 (4.7), 280 (4.14), 289 (4.08), elec
Compound 2 [α]
: parasitaemia reduction in relation to untreated mice. Compounds inhibiting ≤ 30% were considered inactive, 30-50% as partially active and ≥ 50% as active;
controls; significant differences in animal survival (p ≤ 0.05) by Mann-Whitney
to 0.05% and the haematocrit to 1.5%; binding of the HRPII
phenyltetrazolium bromide (MTT) solution (5 mg/mL;
low 10, which were indicative of toxicity; the other purified
, Rio de Janeiro, Vol. (7), November 2015
and β-yohimbine (4) and these compounds correspond to
signals at δH 7.52 (1H, t, J= 7.5 Hz), 7.12 (1H, d, J = 7.5 Hz), correlate with the respective carbons at δ
at δ ) and the other four at δ
methyl group (C-19) at δ
olefinic proton (C-18) at δ = 6.0 Hz) and at δ 4.30 (1H, sl) that correlated with δ 49.7. The H-3 α-config : the steps for extract biofractionation are summarised in Fig. 3; HRPII: histidine and alanine-rich protein; IC
50% parasite growth evaluated in three-four experiments for each test; MG: methoxy-geissoschizol;
and the consequent increase in the SI values; indeed, the
, Rio de Janeiro, Vol. (7), November 2015
δ
5α
β = 13.0; 7.3
6α = 15.0; 4.8
β
14α β
= 6.0; 1.1
21α β
